The referenced U.S. Pat. No. 4,557,245 describes a guide system for saws and the like suitable for cutting concrete, typically concrete or similar hard road surfaces, wall surfaces and the like, for example to provide elongated cuts to permit, subsequently, removal of concrete between the cuts, for example to relocate or repair telephone lines or or other subterranean connections or conduits. The referenced patent describes such a guide rail in which support blocks are provided which engage in openings of an elongated guide rail. This is an excellent connection between the guide rail and the support blocks. The support blocks, typically, rest on or are secured to the surface to be cut.
In actual practice, it has been found that if the base surfaces are uneven, it is not possible to move the support blocks to the most convenient or best support location; they cannot be readjusted, continuously and at random, longitudinally of the guide rail, but can only be relocated wherever the openings in the guide rails have been formed. It is only possible to reposition the support blocks after lifting off a guide rail element, so that the support blocks can be, then relocated in accordance with engagement openings.